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Re: LCD Based Printer; Photopolymer Samples

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  • phife54@ymail.com
    Hi Ali, Im in Kelowna, BC. The printer is still in its early prototype stage, but it is working. Still much work to do to get it out as a DIY kit. As for
    Message 1 of 45 , Feb 24 12:01 PM
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      Hi Ali,

      Im in Kelowna, BC.

      The printer is still in its early prototype stage, but it is working. Still much work to do to get it out as a DIY kit.

      As for answers,

      The color LCD's color filters loose to much light and the red and green block all light leaving holes in the print.

      Im using a glass vat, you cannot use the LCD as a vat bottom because any pressure disturbs the liquid crystal. Light does diffuse, but I have it down to a resonable level using optics and having the light collimated. Cure times are around 8-10seconds, but hope to be less with Fernandos new resins.

      Bulb was only $45, its double ended and a 400w MH, you can use ones for Coral reefs in the 10000k+ range.

      Greyscale LCD's I get from a chinese supplier, they are pricey, $800/LCD with controller. Used ones can be found for $100-200 on ebay, but there is no telling if it will work or not. Most medical LCD require a special video card.

      Once I get some time i'll write up all my finding and help others build and perfect the LCD 3d Printer, It does have some great promise!

      --- In diy_3d_printing_and_fabrication@yahoogroups.com, Ali Punjani <ali.punjani.groups@...> wrote:
      > Hi Nick!
      > Thanks for replying to my post, I was hoping you might.
      > It's great to hear from a fellow Canadian! I'm in Toronto (East), how about
      > you?
      > I think it's awesome that you're planning to release a DIY kit for this
      > sort of project. Also self replication is a good idea. If you're working on
      > software, does that mean the mechanical/optical/chemical parts of the
      > printer are working well now?
      > If you have a minute, I have a few questions for you:
      > What exactly was wrong with a color LCD, were the blue color filters and
      > red/green pixels just blocking too much of the useful light?
      > How did you manage to solve the issue of diffusion of light leaving the LCD
      > Panel? Was it enough to simply use the LCD panel itself as the vat bottom?
      > Does the light from the MH lamp need to be collimated?
      > What kinds of cure times do you get?
      > I read a lot about metal-halide and mercury vapour bulbs over the last few
      > days, and I had looked into some MH lamps made for aquariums - They seem to
      > have the types of spectral output you mentioned. A custom lamp must have
      > been pretty expensive! Similarly with the Monochrome LCD panels - the only
      > place I can find them is on eBay, and they are very expensive - $700 to
      > $1000. I was hoping to get going with a plain color LCD which can be gutted
      > from a photoframe for ~$50. I assume you've found a way to get monochrome
      > LCDs for cheap, if you plan a DIY kit?
      > I'm certainly looking forward to when you have a chance to write about
      > everything you've learned through the testing process. I think I'll start
      > experimenting too, I just finished building a CNC router and I'm looking
      > for a new project to use it for :p
      > Ali
      > On Thu, Feb 21, 2013 at 10:53 PM, phife54@... <phife54@...>wrote:
      > > **
      > >
      > >
      > > Hi Ali,
      > >
      > > A fellow Canadian, where abouts are you?
      > >
      > > I have been developing an LCD based 3d printer for the last 6 months,
      > > While my thread has been quiet for some time, rest assured ive been
      > > plugging away at it.. Its not been a simple matter. Ive done a lot of
      > > testing with different resins, LCD's, Light sources, Lenses, and
      > > Electronics.
      > >
      > > I am hoping to release a DIY kit for others to build their own LCD 3D
      > > printer. Im working with Chris Marion and we are developing a great
      > > machine, I will be using a custom version of Chris's software.
      > >
      > > Dont waste your time with color LCD, you will need a monochrome LCD no
      > > matter what.
      > >
      > > My current setup is using a custom 400w MH bulb on a digital ballast, this
      > > bulb has a small arc and a very high output in the 390-420nm range and has
      > > a large spike at 450nm and not much of the spectrum after that, its a very
      > > nice purple/blue color. Optics are very important, and dealing with the
      > > heat of the 400w MH bulb must also be address.
      > >
      > > I havent had much success with any other bulbs, I was testing with a 150w
      > > MH and a regular 400w MH but they didnt work out.
      > >
      > > The nice thing about the LCD printer is the large build area, I hope to be
      > > able to print the entire structure of the printer with the prototype in a
      > > reprap style. Print panels, add hardware and electronics and you got a
      > > printer. Ive been designing printable panels but there is much to deal with
      > > before I even begin printing other machines.
      > >
      > > You will have to deal with all the issues youve listed and more, and its a
      > > big task. I encourage you to experiment and try. To start off save you
      > > money and dont bother with color LCD's get a monochrome or greyscale LCD
      > > used for medical purposes, x-ray imaging.
      > >
      > > If you wait a couple more months I hope to have a working printer and I
      > > can spend some time getting a DIY kit out there and write up all that ive
      > > learned from my testing ao rhat others can make their own.
      > >
      > > I wish you luck!
      > >
      > > Nick
      > >
      > >
    • chenw1115@yahoo.cn
      holle,do your lcd printer work now?
      Message 45 of 45 , Apr 23, 2014
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        holle,do  your lcd printer work  now?
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